This invention relates to tube having an expandable retention member. In particular, the present invention relates to a tube having an expandable member configured such that, when in an expanded condition, the expandable member decreases the incidence of irritation caused by a distal tip of the tube.
Tubes having expandable members associated therewith are used for a variety of purposes. For example, catheters having inflatable members disposed on a distal end portion thereof are used in angioplasty procedures and in the placement of stents in a patient""s vasculature. Such catheters also are used in other cardiology applications, including the removable positioning of diagnostic equipment in a patient""s vasculature.
Tubes having expandable members associated therewith also are used as gastrostomy tubes. Gastrostomy tubes are used to deliver enteral nutritional products to the gastrointestinal tract of a patient. Gastrostomy tubes are positioned such that an enteral nutritional product is delivered percutaneously through a stoma tract from an external source directly to the patient""s stomach or small bowel. Gastrostomy tubes preferably have expandable retention members mounted thereon, the retention members being constructed to prevent inadvertent removal of the gastrostomy tube from the patient""s stomach.
Retention members preferably are movable between a contracted state and an expanded state. When in the contracted state, the retention member does not prevent the positioning of the catheter or feeding tube in a patient. When the catheter or feeding tube is properly positioned within the patient, the retention member can be placed in its expanded position in order to retain the catheter or feeding tube in the desired position. For example, a portion of a gastrostomy tube can be inserted percutaneously through a patient""s abdominal wall into the patient""s stomach through a stoma tract formed through known techniques. After the retention member has been properly positioned in the patient""s stomach, the retention member is reconfigured into its expanded state in which the external diameter of the retention member is larger than the diameter of the stoma tract, thereby precluding inadvertent withdrawal of the retention member from the patient""s stomach.
Many gastrostomy tubes include an inflatable balloon on the distal end of the feeding tube, the inflatable balloon acting as the retention member. The balloon can be selectively expanded by the introduction of an inflation fluid through an inflation lumen associated with the feeding tube in order to reconfigure the retention member from its contracted state to its expanded state. The inflation fluid can then be withdrawn from the balloon in order to reconfigure the retention member to its contracted state.
It has been found that the distal tip of gastrostomy tubes can come into contact with the interior wall of the patient""s gastrointestinal tract at a position opposite the stoma tract during normal usage, thereby causing irritation to the gastric mucosa. In order to prevent this irritation from occurring, some retention members have been designed such that they provide a cushion between the distal tip of the feeding tube and the gastrointestinal tract.
For example, U.S. Pat. No. 5,997,546 to Foster, et al. discloses a feeding tube having a retention member that is constructed to cover the distal tip of the feeding tube with an inflatable balloon retention member. When the retention member is in its inflated or expanded configuration, the balloon acts as a cushion between the distal tip of the feeding tube and the patient""s gastrointestinal tract. However, due to the fact that the retention member taught by Foster, et al. is attached to an interior wall of the feeding tube, the retention member tends to constrict the distal feeding tube opening defined by the distal tip of the feeding tube, thereby limiting flow through the feeding tube. Further, because the retention member taught by Foster, et al. is attached to an interior wall of the feeding tube, the cost of manufacturing such a feeding tube is substantially higher than the cost of manufacturing other feeding tubes.
In accordance with one aspect of the present invention, a medical device including a tube and a retention member is provided. The tube has a proximal end portion and a distal end portion, the distal end portion including a distal tip. The tube defines a primary lumen therethrough from its proximal end portion to the distal tip. The tube also defines an inflation lumen therethrough from the proximal end portion to a first point on the distal end portion, the first point being spaced from the distal tip of the tube. The tube has an exterior wall and an interior wall, the interior wall being adjacent to the primary lumen defined through the tube.
The retention member defines a lumen therethrough. The retention member includes a sleeve section, a shoulder section, and an expandable section. The sleeve section sealingly engages the exterior wall of the tube along the distal end portion of the tube proximal the distal tip of the tube. The shoulder section extends from the sleeve section. The shoulder section engages the distal tip of the tube. The expandable section extends from the shoulder section. The expandable section is everted about the shoulder section of the retention member, about the sleeve section of the retention member, and about at least a portion of the distal end portion of the tube. The expandable section sealingly engages the exterior wall of the tube along the distal end portion of the tube to define an expandable lumen between the exterior wall of the tube and the expandable section of the retention member. The inflation lumen defined by the tube is in fluid communication with the expandable lumen defined by the exterior wall of the tube and the expandable section of the retention member at the first point on the distal end portion of the tube.
In accordance with a second aspect of the present invention, a retention member for a tube is provided. The retention member defines a lumen therethrough and includes a sleeve section, a shoulder section, and an expandable section. The sleeve section is constructed to sealingly engage an exterior wall of a distal end portion of a feeding tube proximate a distal tip of the tube. The shoulder section extends from the sleeve section and is constructed to engage the distal tip of the tube. The expandable section extends from the shoulder section and is constructed to be everted about the shoulder section of the retention member and the sleeve section of the retention member. The expandable section of the retention member is constructed to sealingly engage the exterior wall of the tube along the distal end portion thereof.